X-ray contrast media

ABSTRACT

The present invention provides new iodo benzene derivatives which have at least two benzene nuclei and one carboxylic group. 
     These derivatives possess a low toxicity and may be used as X-ray contrast media.

This is a division of application Ser. No. 579,279, filed May 20, 1975now U.S. Pat. No. 4,014,986.

This invention relates to new polyiodo benzene derivatives useful asX-ray contrast media.

The present invention relates, more particularly, to new compoundscomprising at least two benzene nuclei and a single carboxyl group whichhave low toxicity, provide good contrast, which may be preparedaccording to industrially useful methods and which, therefore, are ofrelatively low cost.

The formula of a compound comprising two tri-iodo benzene nuclei and asingle carboxyl group as already been given in U.S. Pat. No. 2,708,678.This formula is as follows: ##STR1##

However, the attempts made by Applicant to prepare this compoundaccording to the process described in said patent were all unsuccessful,whatever the operating conditions used.

The present invention relates to compounds of the formula (I) ##STR2##IN WHICH: R₁ represents a hydrogen atom, a radical of the formula##STR3## R₅ and R₆ being a hydrogen atom, a lower alkyl radical, a lowerhydroxyalkyl radical or a lower alkanoyloxyalkyl radical, or a radicalof the formula ##STR4## R₇ being a lower alkanoyl radical and R₈ being ahydrogen atom, a lower alkyl radical, a lower hydroxyalkyl radical or alower alkanoyl radical,

R₂ represents a hydrogen atom, a radical of the formula ##STR5## inwhich R₉ and R₁₀ have the meanings given for R₄ and R₅, or a radical ofthe formula ##STR6## in which R₁₁ has the meaning given for R₇ orrepresents a hydrogen atom and R₁₂ has the meaning given for R₈,

r₃ represents a hydrogen atom, a radical of the formula ##STR7## inwhich R₁₃ and R₁₄ have the meanings given for R₅ and R₆, or a radical ofthe formula ##STR8## in which R₁₅ has the meaning given for R₇ orrepresents a hydrogen atom or a polyhydroxy lower alkanoyl radical andR₁₆ has the meaning given for R₈,

R₄ represents a hydrogen atom, a lower alkyl radical or a lowerhydroxyalkyl radical,

a is 0 or 1

n is an integer from 1 to 5

m is 0 or 1

b is 1 or 2, the sum b + m being 2 or less,

and their lower alkyl esters and their salts with pharmaceuticallyacceptable bases.

By lower alkyl and hydroxyalkyl radicals are essentially meant radicalshaving 1-4 carbon atoms and by lower alkanoyl and hydroxy lower alkanoylradicals are essentially meant radicals having 2-6 carbon atoms.

As salts of acids of the formula (I) may be mentioned, in particular,alkali metal (such as sodium and potassium) salts, the ammonium salts,the alkaline-earth (such as calcium) salts and the organic base salts(e.g. such as ethanolamine or methylglucamine salts).

The compounds according to the present invention may be prepared byreacting an amine of the formula: ##STR9## with a chlorinated compoundof the formula: ##STR10## R₁, R₂, R₃, R₄, a, m and n having theaforesaid meanings.

If desired, this reaction may be followed by a N-alkylation,N-hydroxyalkylation, N-acylation or N-polyhydroxyacylation reaction, bya deacylation reaction, and also by esterification of salt-formingreactions, according to conventional methods.

Amines of the formula (IV) (in which a = 0, n = 1, R₄ = H and R₁ = H,--CONHCH₃ and --NHCOCH₃) are described in U.S. Pat. No. 3,210,412.

The amines of the formula (IV) in which R₄ is hydrogen may be preparedby condensation of an amine of the formula: ##STR11## with an acidchloride having the formula: ##STR12## R₁, a and n having the aforesaidmeanings, with subsequent hydrazinolysis of the resulting condensationproduct of the formula: ##STR13## in which a and n have the aforesaidmeanings and R'₁ has the same meaning as R₁ or, in the case where R₁comprises a hydroxy group, R'₁ represents its acylation product withacid chloride of the formula (VII).

The condensation reaction of the amine of the formula (IV) with acidchloride (VII) is advantageously effected in a polar solvent such asdimethylacetamide or dimethylformamide, at a temperature of 20°-100° C,the acid chloride being used in an excess amount. Reaction time may varyfrom 2 hours to about 4 days.

The hydrazinolysis reaction of the product of the formula (VIII) iscarried out according to usual techniques, by action of hydrazine inaqueous medium (see, in this respect, J. Am. Chem. Soc., 71, 1856(1949); H. R. Ing and R. F. Manske, J. Chem. Soc., 2348 (1926); Chem.Ber. 83 244 (1950)). A large excess of hydrazine is advantageously used(4-8 moles per mole of product of the formula (VIII)).

The amines of the formula (IV) in which n = 1 and a = 0 and R₄ is alower alkyl radical may also be prepared by reacting a compound havingthe formula: ##STR14## with an alkylating agent, to give a compound ofthe formula: ##STR15## in which R₄ is a lower alkyl radical, withsubsequent reaction of ammonia with the resulting compound.

A preferred class of compounds of the formula (I) is represented by thecompounds having the formula: ##STR16## in which: R₁ represents ahydrogen atom, a radical having the formula ##STR17## R₅ and R₆ beingeach a hydrogen atom, a lower alkyl radical, a lower hydroxyalkylradical or a lower alkanoyloxyalkyl radical, or a radical of the formula##STR18## R₇ being a lower alkanoyl radical and R₈ being a hydrogenatom, a lower alkyl or lower hydroxyalkyl radical,

R₂ represents a hydrogen atom, a radical having the formula ##STR19## inwhich R₉ and R₁₀ have the meanings given for R₅ and R₆, or a radical ofthe formula ##STR20## in which R₁₁ has the meaning given for R₇ orrepresents a hydrogen atom and R₁₂ has the meaning given for R₈,

R₄ represents a hydrogen atom, a lower alkyl radical or a lowerhydroxyalkyl radical,

R₁₅ represents a hydrogen atom, a lower alkanoyl radical or apolyhydroxy lower alkanoyl radical,

R₁₆ represents a hydrogen atom, a lower alkyl radical, a lowerhydroxyalkyl radical or a lower alkanoyl radical,

a is 0 or 1

n is an integer from 1 to 5

b is 1 or 2

and the different R₂, R₄ and n which exist when b = 2 may have the sameor different meanings, and their lower alkyl esters and their salts withpharmaceutically acceptable bases.

Said compounds of the formula (II) may be prepared by condensing anamine of the formula (IV) as previously defined with an acid chloridehaving the formula: ##STR21## This condensation reaction isadvantageously effected within a polar solvent such asdimethylacetamide,dimethylsulfoxide,dimethylformamide or a mixturewater-dioxane, at a temperature of 20°-60° C, in the presence of an acilbinding agent such as triethylamine or sodium carbonate in excessamount. Reaction time may vary from 2 hrs to about 4 days.

To obtain a compound of the formula (II) in which R₄ is an alkyl orhydroxyalkyl radical, a compound of the formula (II) in which R₄ ishydrogen may be reacted with an alkylating or hydroxyalkylating agent,according to conventional methods.

To obtain a compound of the formula (II) in which R₁₅ is a loweralkanoyl radical or a polyhydroxy lower alkanoyl radical, a compound ofthe formula (II) in which R₁₅ and R₁₆ are hydrogen atoms may be reactedwith an acylating or polyhydroxyacylating agent, according toconventional methods.

Conversely, a compound of the formula (II) in which R₁₅ and R₁₆ arehydrogen atoms may be obtained by saponification (deacylation) ofN-acylated compounds of the formula (II).

The compounds of the formula (II) in which b = 2, may be prepared usingas amine of the formula (VI) a compound of the formula (II) in which R₁₅and R₁₆ are hydrogen atoms.

Another preferred class of compounds of the formula (I) is representedby the compounds having the formula: ##STR22## in which: R₁ represents ahydrogen atom, a radical having the formula ##STR23## in which R₅ and R₆are a hydrogen atom, a lower alkyl radical or a lower hydroxy alkylradical or a radical of the formula ##STR24## in which R₇ is a loweralkanoyl radical and R₈ is a hydrogen atom, a lower alkyl radical or alower hydroxyalkyl radical,

R₂ represents a hydrogen atom, a radical having the formula ##STR25## inwhich R₉ and R₁₀ have the meanings given for R₄ and R₅, or a radical ofthe formula ##STR26## in which R₁₁ has the meaning given for R₇ orrepresents a hydrogen atom and R₁₂ has the meaning given for R₈,

R₃ represents a hydrogen atom, a radical having the formula ##STR27## inwhich R₁₃ and R₁₄ have the meanings given for R₅ and R₆, or a radical ofthe formula ##STR28## in which R₁₅ has the meaning given for R₇ orrepresents a hydrogen atom and R₁₆ has the meaning given for R₈,

R₄ represents a hydrogen atom, a lower alkyl radical or a lowerhydroxyalkyl radical,

and their lower alkyl esters and their salts with pharmaceuticallyacceptable bases.

Said compounds of the formula (III) may be prepared by reacting an amineof the formula (IV) as previously defined (in which a = 0) with achlorinated compound of the formula: ##STR29##

This reaction is advantageously effected in basic aqueous medium, forexample in excess normal sodium hydroxide, at a temperature of 60°-90°C. The reaction time may vary from 6 to 48 hours.

The chlorinated compounds of the formula (Vb) may be prepared byreaction of chloroacetyl chloride with the corresponding aniline, underconventional conditions, followed, if desired, by a saponification.

The following examples are given to illustrate the invention. Thepreparation of amines of the formula (IV), of derivatives of the formula(V) and of compounds of the formula (I) is described in followingsections A, B and C, respectively.

In said examples, purity controls were effected by:

1. Thin-layered chromatography (TLC) over fluorescent Silicagel plate(Merck F 254 grade) in the following eluents:

1 -- Benzene/methylethyl ketone/formic acid (60:25:20) Eluent 1.

2 -- Ethyl acetate/isopropanol/ammonia (55:35:40) Eluent 2.

3 -- Ethyl acetate/isopropanol/ammonia (35:35:40) Eluent 3.

4 -- n-Butanol/acetic acid/water (50:11:25) Eluent 4.

Note: With certain TLC eluents (particularly eluent 4), it is possibleto evidence the different isomers of acids containing a N-methylN-acylamino benzoic function.

Thus, a pure mono-N-methyl compound of the formula (I) will give 2 spots(slightly spaced apart, but clearly distinct, and in varying ratiosaccording to the acids), and a di-N-methyl compound will give 3 spots.

2. Purity determination according to:

1 -- Halogen titration

2 -- Carboxylic acid titration : back-titration with sodium hydroxide.

3 -- Labile hydrogen and carboxylic acid titration with sodium methoxidein non-aqueous medium, in the presence of azoviolet.

4 -- Titration of carboxylic acid in dimethylformamide solution, bymeans of tetrabutylammonium hydroxide in isopropanol solution.

5 -- Titration of aliphatic amines, by means of perchloric acid inacetic medium.

A. PREPARATION OF AMINES OF THE FORMULA (IV) I. Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-aminoacetylamino-benzoic acid(Compound I) a. Preparation of2,4,6-triiodo-3-N-phthalimido-acetoxyethylcarbamyl-5-phthalimidoacetylamino-benzoicacid ##STR30##

2,4,6-Triiodo-3-N-hydroxyethylcarbamyl-5-amino-benzoic acid (180 g; 0.3mole) is dissolved in dimethylacetamide (300 ml). Phthalylglycine acidchloride (170 g; 0.76 mole) is added portionwise (while cooling over anice bath). After stirring overnight at room temperature, the reactionmixture is diluted with water (1000 ml). Precipitation occurs. Theresulting material is suction filtered, washed repeatedly with water,suction filtered and oven-dried, to give 275 of white material. Yield:95%.

Purity control:

Tlc eluent 1.

Rf of the starting triiodo acid: 0.4

Rf of the starting phthalylglycine: 0.77

Rf of the condensation product: 0.68

b. Preparation of2,4,6-triiodo-3-N-hydroxyethyl-carbamyl-5-aminoacetamido-benzoic acid##STR31##

The preceding product (197 g; 0.20 mole) is suspended in water (600 ml)and hydrazine hydrate (60 g) and heated at 80° c during 2 hours, withstirring (dissolution occurs). Crystallization occurs during thereaction. After cooling, suction filtering, washing and oven-drying,there are obtained 125 g of product. Yield: 95%.

Purity control:

1. TLC eluent 1

Rf of the starting material: 0.68

Rf of the product obtained: 0.05

An orange-yellow spot is obtained on development with ninhydrin.

2. Purity of the product according to the iodine titration: 97.7%

3. Purity of the product according to titration with sodium hydroxide:100%

II. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-γ-aminobutyrylamino-benzoic acid(Compound II)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-N-methyl-carbamyl-5-amino-benzoic acid as iodo startingmaterial and γ-phthalimidobutyric acid chloride as acid chloride.

III. Preparation of2,4,6-triiodo-3-N-methyl-carbamyl-5-aminoacetylamino-benzoic acid(Compound III)

the same procedure is used as for Compound I, using2,4,6-triiodo-3-N-methyl-carbamyl-5-aminobenzoic acid as startingmaterial.

In addition, the crude product is purified: it is taken up into 95%ethanol (about 3000 g/5 liters). The mixture is heated to refluxingtemperature and is then filtered hot. Overall yield condensation +purification = 62.5%.

IV. Preparation of2,4,6-triiodo-3-acetamido-5-aminoacetamidomethyl-benzoic acid (CompoundIV)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-acetamido-5-aminomethyl-benzoic acid as startingmaterial, obtained under the following conditions:

2,4,6-Triiodo-2,4,6-acetamido-5-acetamidomethyl-benzoic acid (111 g;0.177 mole) (Swiss Pat. No. 13,788/62) is dissolved in 10N sodiumhydroxide (220 ml). The resulting solution is heated 2 hours at 70° C,after which it is cooled to 0° C and adjusted at pH 7 with concentratedhydrochloric acid. It is then left to crystallize overnight in therefrigerator and is then suction filtered, washed repeatedly with water,suction filtered and oven-dried, to give 100 g of product. Yield: 96%.

Purity control:

1. TLC eluent 1

Rf of the starting material: 0.30

Rf of the product obtained: 0.25

2. Purity of the product according to the iodine titration: 99.5%

Condensation of 2,4,6-triiodo-3-acetamido-5-aminomethyl-benzoic acid andphthalylglycine chloride. The triiodo acid (100 g; 0.17 mole) isdissolved in DMAC (200 ml). Phthalylglycine acid chloride (55 g; 0.25mole) is added thereto and the mixture is allowed to react overnight atroom temperature. A further amount of phthalylglycine acid chloride (20g) is added after 24 hours, and, 24 hours later, a further amount (45 g)of phthalylglycine acid chloride is added.

Precipitation of the product, washing, suction filtering, drying andsubsequent hydrazinolysis are then carried out as described for CompoundI.

V. Preparation of 2,4,6-triiodo-3-ε-aminocaproylamino-benzoic acid(Compound V)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-amino-benzoic acid as iodo starting material andε-phthalimidocaproic acid chloride.

VI. Preparation of 2,4,6-triiodo-3-aminoacetamido-benzoic acid (CompoundVI)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-amino-benzoic acid as iodo starting material.

VII. Preparation of 2,4,6-triiodo-3-acetamido-5-aminoacetamido-benzoicacid (Compound VII)

The same procedure is used as for Compound I, using2,4,6-3-acetamido-5-amino-benzoic acid as iodo starting material. VIII.Preparation of2,4,6-triiodo-3-N-methyl-carbamyl-5-N-methyl-N-aminoacetylamino-benzoicacid (Compound VIII)

a. 2,4,6-Triiodo-3-N-methyl-carbamyl-5-N-methyl-chloroacetamido-benzoicacid:

Dimethyl sulfate (380 ml; 4 moles) is added dropwise, at 5°-10° C, to asolution of 2,4,6-triiodo-3-N-methyl-carbamyl-5-chloroacetamido-benzoicacid (1300 g; 2 moles) (U.S. Pat. No. 3,210,412) in a 2N sodiumhydroxide solution (2 liters). When addition is complete, the reactionmixture is allowed to warm to room temperature and stirring is continueda further 20 hours. The reaction mixture is then filtered, a slightinsoluble is removed, and the material is made acidic to pH 1 withconcentrated hydrochloric acid. The resulting precipitate is suctionfiltered, washed repeatedly with water and dried at 60° C. Purificationis carried out by dissolving the crude material in 900 ml 2N sodiumhydroxide and salting out with sodium chloride (1000 g). After stirring24 hours at room temperature, the precipitate is suction filtered andredissolved in water (2500 ml). After which it is filtered and madeacidic to pH 1 with concentrated hydrochloric acid. It is thenrepeatedly washed with water, suction filtered, dried at 60° C, to give672 g of product (Yield: 51%).

Purity control:

1. TLC eluent 2

Rf of starting material: 0.1

Rf of the methyl product: 0.2 and 0.25 (2 isomers)

2. Purity: iodine titration: 97%, chlorine titration 104%

b.2,4,6-triiodo-3-N-methyl-carbamyl-5-N-methyl-N-aminoacetyl-amino-benzoicacid:

The preceding acid (314 g; 0.49 mole) is dissolved in 3500 mlconcentrated ammonia and heated 20 hours at 60° C. After evaporation todryness, in vacuo, the material is taken up into 300 ml water and madeacidic with sulfur dioxide. It is then left to crystallize in therefrigerator during 48 hours, suction filtered, washed repeatedly withwater and dried in an oven at 80° C, to give 160 g (Yield: 51%) ofproduct.

Purity control:

1. TLC eluent 3

Rf of the product obtained: 0.75

2. Purity: titration with sodium hydroxide: 102%

Purity: titration with sodium methoxide: 98%

IX. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methyl-N-acetylamino-5-aminoacetylamino-benzoyl)-glycylamino-benzoicacid (Compound IX)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methyl-N-acetylamino-5-amino-benzoyl)-glycylamino-benzoicacid (Compound 15 described hereinafter) as iodo starting material, thesole exception being a longer reaction time (4 days at roomtemperature).

X. Preparation of 2,4,6-triiodo-3-N-methyl-N-aminoacetylamino-benzoicacid (Compound X) a. Preparation of2,4,6-triiodo-3-chloroacetamido-benzoic acid (according to U.S. Pat. No.3,210,412).

Purity control:

1. TLC eluent 2

Rf of starting material: 0.3

Rf of the product obtained: 0.25

2. Purity: titration with sodium hydroxide: 99.8%

b. 2,4,6-Triiodo-3-N-methyl-N-chloroacetylamino-benzoic acid

The above product (591.5 g; 1 mole) is dissolved in 5N sodium hydroxide(2.3 moles) and acetone (100 ml).

Methyl iodide (1.3 mole) is added dropwise, while maintaining thetemperature at 10° C by means of an ice-bath. After stirring during 16hours at room temperature, the reaction mixture is poured over 2 litersdilute (1/10) hydrochloric acid, while cooling by means of an ice-bath.The resulting precipitate is suction filtered, washed repeatedly withwater and dried in an oven at 50° C, to give 591 g (Yield: 85%) ofproduct.

Purity control:

1. TLC eluent 2

Rf of starting material: 0.25

Rf of the methyl product (separation of 2 isomers): 0.35 and 0.45

2. Purity: chlorine titration: 92%

iodine titration: 100%

Purity: titration with sodium methoxide: 92%

c. 2,4,6-Triiodo-3-N-methyl-N-aminoacetylaminobenzoic acid:

The preceding acid (590 g; 0.90 mole) is dissolved in 9 litersconcentrated ammonia. Dissolution is substantially complete (filtrationremove 3 g of insoluble matter which is the methyl ester of the startingacid).

The resulting solution (pale yellow) is heated during 20 hours at 60° Cand then concentrated to 2 liters, in vacuo. The ammonium saltcrystallizes; it is suction filtered and redissolved in water (500 ml)and the minimum volume of sodium hydroxide, after which it isreprecipitated at pH 4 with acetic acid, to give, after suctionfiltering, repeated washing with water, suction filtering and drying 316g of white product (Yield: 52%).

Purity control:

1. TLC eluent 1

Rf of starting material: 0.9

Rf of the product obtained: 0.25 (yellow spot on development withninhydrin).

2. Purity: titration with sodium hydroxide: 98.5%

Purity: titration with sodium methoxide: 100%.

XI. Preparation of 2,4,6-triiodo-3-N-γ-aminobutyrylamino-benzoic acid(Compound XI)

The same procedure is used as for Compound II, using2,4,6-triiodo-3-amino-benzoic acid as iodo starting material.

In this case, it is necessary to purify the resulting crude product bydissolution of 350 g in 4 liters water and 280 ml concentrated sulfuricacid.

The insoluble impurities are filtered off, the solution is neutralizedand the amino is then reprecipitated with acetic acid at pH 4, to give309 g of purified product.

XII. Preparation of 2,4,6-triiodo-3-β-aminopropionylaminobenzoic acid(Compound XII)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-amino-benzoic acid as iodo starting material andβ-phthalimidopropionic acid chloride.

XIII. Preparation of2,4,6-triiodo-3-N-methyl-N-acetylamino-5-amino-acetamido-benzoic acid(Compound XIII)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-N-methyl-N-acetylamino-5-amino-benzoic acid (U.S. Pat.No. 3,178,473) except that:

1. The condensation product with phthalylglycine is washed (1554 g ofproduct in 2 liters 95% ethyl alcohol, to give 1200 g purified product).

2. The crude hydrazinolysis product is purified by dissolving 267 g in550 ml dilute sulfuric acid (1/10) at 80° C.

It is filtered hot and 25 g phthalhydrazide are removed: ##STR32##

The sulfruic filtrate is treated with charcoal and neutralized to pH 4-5with ammonia. It is then crystallized, repeatedly washed with water,suction filtered and dried in an oven at 70° C, and then at 105° C, togive 211 g of white material.

3. 390 g of white material of same grade as the preceding 211 g arerecovered by treating the hydrazinolysis liquid with sulfuric acid inthe hot.

XIV. Preparation of2,4,6-triiodo-3-N-hydroxyethyl-carbamyl-5-amino-butyrylamino-benzoicacid (Compound XIV)

The same procedure is used as for Compound II, using2,4,6-triiodo-3-hydroxyethyl-carbamyl-5-amino-benzoic acid as iodostarting material.

XV. Preparation of2,4,6-triiodo-3-N-methyl-carbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-aminoacetamido-benzoyl)-glycyl-N-methylamino-benzoicacid (Compound XV)

The same procedure is used as for Compound I, using compound 14a,described hereinafter, as iodo starting material.

XVI. Preparation of2,4,6-triiodo-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-aminoacetamido-benzoyl)-glycyl-amino-benzoicacid (Compound XVI)

The same procedure is used as for Compound I, using compound 34,described hereinafter, as iodo starting material.

XVII. Preparation of2,4,6-triiodo-3-N-hydroxyethyl-carbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-aminoacetamido-benzoyl)-glycly-amino-benzoicacid (Compound XVII)

The same procedure is used as for Compound I, using compound 3a,described hereinafter, as starting material.

XVIII. Preparation of2,4,6-triiodo-3-N-methyl-carbamyl-5-amino-propionylamino-benzoic acid(Compound XVIII)

The same procedure is used as for Compound I, using2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoic acid as startingmaterial.

In Table I are set forth data relating to the preparation of amines ofthe formula (IV) by condensation and hydrazinolysis and to the resultingamines. In Table II are set forth data relating to the preparation ofamines of the formula (IV) from chlorinated derivatives of the formula(IX) and to the resulting amines.

In Table III, are illustrated the structural formulae of the amines ofgeneral formula (IV) thus prepared.

In following Table I:

1. after washing with DMF in the hot

2. in benzene/methylethylketone/formic acid (80:20:10) eluent.

                  TABLE I                                                         ______________________________________                                        Triiodo                                                                       starting                Amines obtained                                       material   Condensation by hydrazinolysis                                     Rf in      product      Rf in   Rf in                                               eluent   Rf in          eluent                                                                              eluent                                    Amine 1        eluent 1 Yield 1     2     Yield                               ______________________________________                                        I     0.4      0.68     95%   0.05  0.5   95%                                 II    0.7      0.5      100%  0.05  0.15  95%                                                                     eluent                                                                         4                                        III   0.65     0.4      100%  0.05  0.45  62%                                                               0.1                                             IV    0.1      0.45     89%   0.05  0.5   85%                                 V     0.9      0.75     100%  0.15        87%                                 VI    0.7      0.55 (2) uniso-                                                                              0.5   0.1   71%                                                         lated       eluent                                                                              (overall                                                                 3    yield)                              VII   0.5      0.4      85%   0.05  0.44  73%                                 IX    0.4      0.3      83%   0.05  0.55/ 83%                                                                     0.60                                      XI    0.9      0.80     100%  0.2   0.05  81%                                 XII   0.9      0.85     100%  0.2   0.2   75%                                                                     0.1 in                                                                        eluent                                                                         4                                        XIII  0.65     0.4      90%   0.05  0.45  66%                                                                     0.53                                      XIV   0.4      0.6      uniso-                                                                              0.0   0.1   58%                                                         lated             (overall                                                                      yield)                              XV    0.4      0.35     72%   0.0   0.25  50%                                 XVI   0.4      0.3      92%   0.05  0.1 in                                                                              41%                                                                     eluent                                                                         3                                        XVII  0.15     0.3      97%   0.0   0.5   50% (1)                             XVIII 0.7      0.45     85%   0.05  0.02  53%                                 ______________________________________                                    

                  TABLE II                                                        ______________________________________                                        Triiodo                                                                       starting Chlorinated                                                          mater-   condensation                                                         ial      product         Amine                                                     Rf in   Rf in   Rf in       Rf in Rf in                                  A-   eluent  eluent  eluent      eluent                                                                              eluent                                 mine 2       2       1     Yield 1     2     Yield                            ______________________________________                                                     0.2                 0.3 in                                       VIII 0.1     and     0.5   51%   eluent                                                                              0.75  51%                                           0.25                4                                                         0.3                       0.15                                   X    0.25    and     0.9   97%   0.25  and   54%                                           0.25                      0.25                                   ______________________________________                                         ##STR33##

B. PREPARATION OF DERIVATIVES OF THE FORMULA (V) XIX. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-N-acetyl-N-methylamino-benzoic acidchloride (Compound XIX

2,4,6-Triiodo-3-methylcarbamyl-5-N-acetyl-N-methylaminobenzoic acid (50g) (described in French Pat. No. 2,085,636) is suspended in thionylchloride (90 ml). The suspension is heated at 65° C during 5 hours, withstirring. The resulting slurry is allowed to cool. The acid chloride issuction filtered and washed with diisopropyl ether; it is then dried invacuo, to give 37 g of product (Yield: 73%).

Purity control:

Tlc after reaction with excess propylamine in dimethylacetamide: Eluent1.

Rf starting material: 0.5

Rf of propylamine condensate: 0.83

XX. Preparation of 2,4,6-triiodo-3-methylcarbamyl-5-amino-benzoic acidchloride (Compound XX)

The same procedure is used as for compound XIX, using2,4,6-triiodo-3-N-methylcarbamyl-5-amine-benzoic acid as startingmaterial (Yield: 85%).

Purity control:

1. TLC: same technique as with the preceding product, but aftercondensation with ethanolamine

Rf of starting acid: 0.8

Rf of condensate: 0.4

2. TLC in acetone/chloroform/acetic acid (50:40:10) eluent:

Rf of acid: 0.55

Rf of acid chloride: 0.95

XXI. Preparation of 2,4,6-triiodo-5-N-methyl-N-acetylaminobenzoic acidchloride (Compound XXI)

The same procedure is used as for Compound XIX, using2,4,6-triiodo-3-N-methyl-N-acetylamino-benzoic acid as starting material(Yield: 85%).

XXII. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-N-diacetylamino-benzoic acid chloride(Compound XXII) a. Diacetylation of2,4,6-triiodo-3-N-methylcarbamyl-5-aminobenzoic acid (described in U.S.Pat. No. 3,145,197).

800 g of triiodo acid (1.4 mole) are heated overnight at 120° C in 1.6liter acetic anhydride. The reaction mixture is cooled and an insolublematerial (123 g), consisting of starting material, is filtered off. Thereaction liquid is slowly poured over water (3 liters) and ice (1 kg).The resulting two phases are decanted. The lower phase is taken up intowater (2.4 liters) to give a gum which is redissolved in acetic acid(800 ml). This solution is precipitated by addition of water (5.4liters) and ice (1 kg). The resulting material is suction filtered andwashed repeatedly with water, to give 500 g of wet product which issubsequently used as such.

b. Preparation of the acid chloride

The 500 g of crude product are gradually added to 830 ml thionylchloride. The temperature decreases. After 30 minutes, 300 ml thionylchloride are added, followed by 400 ml thionyl chloride 30 minuteslater, after which the reaction is completed by heating two hours at 70°C. The thionyl chloride is evaporated in vacuo and the resultingmaterial is taken up into benzene and is then evaporated to dryness, invacuo. The latter benzene-evaporation treatment is repeated twice, togive 305 g of beige product (overall yield of 38% with respect to the2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoic acid actually used).

Purity control: Same technique as with compound XIX, after condensationwith propylamine.

1. TLC: acetone/chloroform/acetic acid (5:4:1) eluent: Rf : 0.83

2. Purity according to iodine titration: 97%

Purity according to titration with sodium methoxide: 101%

XXIII. Preparation of2,4,6-triiodo-3-N-acetoxyethylcarbamyl-5-N-diacetylamino-benzoic acidchloride (Compound XXIII) a. Triacetylation of2,4,6-triiodo-3-N-hydroxyethyl-carbamyl-5-amino-benzoic acid

2,4,6-Triiodo-3-N-hydroxyethylcarbamyl-5-aminobenzoic acid (60.2 g; 0.1mole) is dissolved in acetic anhydride (150 ml). The solution is heatedat 160° C during 48 hours. After cooling, the solution is poured over250 ml water. The resulting gum is taken up into 3 × 150 ml chloroform.The chloroform is washed with 2 × 100 ml water and dried over calciumchloride; the resulting material is filtered and evaporated in vacuo, togive 60 g of oily product (Yield: 82%).

Purity control:

1. TLC: Eluent 1

Rf of triacetyl -- product: 0.75

2. Titration: product is unisolated

b. Preparation of the acid chloride

2,4,6-Triiodo-3-N-acetoxyethyl-carbamyl-5-diacetylaminobenzoic acid (60g; 0.082 mole) is dissolved in thionyl chloride (150 ml). The solutionis heated to 80° C during 4 hours. After evaporation in vacuo, theresidue is taken up into 100 ml chloroform. A slight insoluble isremoved and the acid chloride is precipitated by slowly adding diethylether. The resulting material is suction-filtered and dried, to give 45g of product (i.e., a yield of 73% with respect to the triacetylproduct).

Purity control:

1. TLC eluent 1

Rf of acid chloride: 0.9

2. Titration: unisolated.

XXIV. Preparation of2,4,6-triiodo-3-N-acetoxyethyl-carbamyl-5-N-methyl-N-acetylamino-benzoicacid chloride (Compound XXIV) a. Acetylation of2,4,6-triiodo-3-N-hydroxyethyl-carbamyl-5-N-methyl-N-acetylamino-benzoicacid

Acetyl chloride (157 g; 2 moles) is added to a suspension of2,4,6-triiodo-3-N-hydroxyethyl-carbamyl-5-N-methyl-N-acetamidobenzoicacid (658 g; 1 mole) (described in French Pat. No. 2,074,734) in dioxane(2 liters).

The reaction mixture is heated at 80° C during 20 hours. Dissolutionoccurs. The dioxane is evaporated in vacuo, to give 700 g of acid (i.e.,a yield of 100%).

Purity control:

1. TLC eluent 1

Rf of starting material: 0.25

Rr of product obtained: 0.45

2. Purity according to titration: the product is unisolated

b. Preparation of the acid chloride

The acid obtained above (790 g; 1 mole) is dissolved in thionyl chloride(1200 ml). The reaction mixture is heated at 50° C during two hours. Ared solution is obtained. After 48 hours in the refrigerator, thecrystalline material is suction-filtered; it is then washed repeatedlywith isopropyl ether and dried, to give 485 g of product (Yield: 67%).

Purity control:

1. TLC: eluent 1

Rf of starting material: 0.45

Rf of product obtained: 0.8

2. Purity according to iodine titration: 100%

In following Table IV are set forth the structural formulae of the acidchlorides thus prepared and also those of other know chlorides which areused to prepare the compounds of the general formula I.

                  TABLE IV                                                        ______________________________________                                         ##STR34##                  XIX                                                ##STR35##                  XX                                                 ##STR36##                  XXI                                                ##STR37##                  XXII                                               ##STR38##                  XXIII                                              ##STR39##                  XXIV                                               ##STR40##                  XXV                                                ##STR41##                  XXVI                                              ______________________________________                                    

xxvii. preparation of2,4,6-triiodo-3,5-bis-(N-hydroxyethylcarbamyl)-chloracetanilide

2,4,6-Triiodo-3,5-bis-(N-hydroxyethyl-carbamyl)-aniline (645 g; 1 mole)(described in French Pat. No. 1,172,953) is dissolved in 2 liters DMAC(dimethylacetamide), at room temperature. Chloroacetyl chloride (430 ml;6 moles) is slowly added thereto, while cooling by means of an ice-bath.Stirring is maintained 3 hours at room temperature.

Completion of the reaction is controlled by thin-layer chromatographyover Silicagel plate in ethyl acetate/isopropanol/ammonia (55:35:20)eluent. Rf = 0.5. The reaction mixture is poured over water (6 liters),to give a very fine white precipitate which is not readily suctionfiltered. After washing with water, the resulting2,4,6-triiodo-3,5-bis-(N-chloroacetoxyethylcarbamyl)-chloroacetanilideis saponified by stirring in 2 liters 2N sodium hydroxide at roomtemperature during two hours, and then at 40° C during two hours.

Chromatographic control over Silicagel plate, in the same eluent: Rf =0.35.

The reaction mixture is cooled and neutralized with concentratedhydrochloric acid (100 ml), and stirring is continued overnight at roomtemperature; after which it is suction filtered, washed with water,suction filtered, dried overnight at 60° C, to give 672 g of product(Yield: 93%).

Purity control:

Titration with sodium methoxide: 105%

Iodine titration: 99%

Chlorine titration: 102.8%

C. PREPARATION OF COMPOUNDS OF THE FORMULA (I) 1) Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methyl-N-acetylaminobenzoyl)glycylamino-benzoicacid (Compound 1) a. Condensation

2,4,6-Triiodo-3-N-hydroxyethylcarbamyl-5-aminoacetamidobenzoic acid(Compound I; 165 g; 0.25 mole) is suspended in a mixture ofdimethylacetamide (250 ml) and triethylamine (58.50 g).2,4,6-Triiodo-3-N-methylcarbamyl-5-N-methyl-N-acetylamino-benzoic acidchloride (Compound XIX; 163 g; 0.25 mole) is added to the suspensionwhich is then vigorously stirred at 50° C during 6 hours. TLC is used tocontrol that less than 3% starting materials remain.

The solution is poured over water (1240 ml). The slight precipitateformed is suction filtered. Hydrochloric acid is added to the filtrateto clearly acidic pH. The material is suction filtered, washed withwater and dried in an oven at 80° C, to give 186 g of crude product(Yield: 61%).

Purity control:

1. TLC eluent 1:

Rf of starting amine: 0.05

Rf of acid chloride: 0.80

Rf of condensate: 0.15

2. Purity of the product according to titration with sodium hydroxide:95%

Purity of the product according to titration with sodium methoxide:98.5%

Purity of the product, according to iodine titration: 97%.

b. Purification

Purification is effected by crystallization in the hot, in 95% ethanol.

The product (186 g) is suspended in 95% ethanol (400 ml) and thesuspension is then heated to the refluxing temperature. Completedissolution occurs and, after 6 hours, the product crystallizes. Totalheating time is 36 hours. The resulting material is allowed to cool.

After suction-filtering, the wet material is dissolved in an aqueoussodium hydroxide solution (400 ml), after which it is adjusted at pH 4-5with acetic acid and is then charcoaled twice. The product is thenfiltered, made acidic to markedly acidic pH with concentratedhydrochloric acid, filtered, washed with water, suction filtered anddried, to give 115 g of pure product (Yield: 62%).

Purity control:

1. TLC: same results as after condensation.

2. Purity: titration with sodium hydroxide: 101%

Purity: titration with sodium methoxide: 98.5%

Purity: iodine titration: 100.5%.

2. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 2)

The same procedure is used as for Compound 1, from amine II and acidchloride XIX.

3. Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)-glycylaminobenzoic acid (Compound 3)

This acid is prepared according to two methods:

a. From2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoyl)-glycylamino-benzoicacid. (Compound 3a). Compound 3a is prepared using the same procedure asfor Compound 1, from amine I and acid chloride XX. Acetylation ofCompound 3a gives Compound 3.

b. From2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-diacetylamino-benzoyl)-glycylamino-benzoicacid (Compound 3b). Compound 3b is prepared using the same procedure asfor Compound 1, from amine I and acid chloride XXII. Saponification ofCompound 3b gives Compound 3.

4. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-N-acetylamino-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 4)

a.2,4,6-Triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-acetoxyethylcarbamyl-5-N-diacetylamino-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 4a); obtained using the procedure described for Compound1, from amine II and acid chloride XXIII.

b. Saponification of Compound 4a gives Compound 4.

5. Preparation of2,4,6-triiodo-3-acetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-glycylmethylamino-benzoicacid (Compound 5).

The same procedure is used as for Compound 1, from amine IV and acidchloride XIX.

6. Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-acetamido-5-N-methylacetamido-benzoyl)-glycylamino-benzoicacid (Compound 6)

a.2,4,6-Triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-amino-5-N-methylacetamido-benzoyl)-glycylamino-benzoicacid (Compound 6a): Obtained using the procedure described for Compound1, from amine I and acid chloride XXV.

b. Acetylation of Compound 6a gives Compound 6.

7. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-N-methylacetamido-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 7)

a.2,4,6-Triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-acetoxyethylcarbamyl-5-N-methylacetamido-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 7a): obtained using the procedure described for Compound1, from amine II and acid chloride XXIV.

b. Saponification of Compound 7a gives Compound 7.

8. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-N-methylacetamido-benzoyl)-glycylamino-benzoic acid (Compound 8)

a.2,4,6-Triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-acetoxyethylcarbamyl-5-N-methylacetamido-benzoyl)-glycylamino-benzoicacid (Compound 8a): Obtained using the procedure described for Compound1, from amine III and acid chloride XXIV.

b. Saponification of Compound 8a gives Compound 8.

9. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-glycylamino-benzoicacid (Compound 9)

The procedure described for Compound 1 is used, from amine III and acidchloride XIX.

10. Preparation of2,4,6-triiodo-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-γ-aminocaproylamino-benzoicacid (Compound 10)

The procedure described for the preparation of Compound 1 is used, fromamine V and acid chloride XIX.

11. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylacetamido-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 11)

The procedure described for the preparation of Compound 1 is used, fromamine II and acid chloride XXI.

12. Preparation of2,4,6-triiodo-3-(2,4,6-triiodo-3-acetamidobenzoyl)-glycylamino-benzoicacid (Compound 12)

a. 2,4,6-Triiodo-3-(2,4,6-triiodo-3-amino-benzoyl)-glycylamino-benzoicacid (Compound 12a): Obtained using the procedure described for thepreparation of Compound 1, from amine VI and acid chloride XXVI.

b. Acetylation of Compound 12a gives Compound 12.

13. Preparation of2,4,6-triiodo-3-(2,4,6-triiodo-3-N-methylacetamido-benzoyl)-glycyl-N-methylamino-benzoicacid (Compound 13)

The procedure described for the preparation of Compound 1 is used, fromamine X and acid chloride XXI.

14. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)-glycyl-N-methylamino-benzoicacid (Compound 14)

a.2,4,6-Triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoyl)-glycyl-N-methylamino-benzoicacid (Compound 14a): Obtained using the procedure described for Compound1, from amine VIII and acid chloride XX.

b. Acetylation of Compound 14a gives Compound 14.

15. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylacetamido-5-amino-benzoyl)-glycylamino-benzoicacid (Compound 15)

The procedure described for Compound 1 is used, from amine III and acidchloride XXV.

16. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-[2,4,6-triiodo-3-N-methylacetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)glycylamino-benzoyl]-glycylamino-benzoicacid (Compound 16)

a.2,4,6-Triiodo-3-N-methylcarbamyl-5-[2,4,6-triiodo-3-N-methylacetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoyl)glycylamino-benzoyl]glycyl-amino-benzoicacid (Compound 16a): Obtained using the procedure described for Compound1, from amine IX and acid chloride XX.

b. Acetylation of Compound 16a gives Compound 16.

17. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-[2,4,6-triiodo-3-N-methylacetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)glycyl-aminobenzoyl]-glycyl-amino-benzoicacid (Compound 17)

The procedure described for Compound 1 is used, from amine IX and acidchloride XIX.

18. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylacetamido-benzoyl-glycyl)-amino-benzoicacid (Compound 18)

The procedure described for Compound 1 is used, from amine III and acidchloride XXI.

19. Preparation of2,4,6-triiodo-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)glycylamino-benzoicacid (Compound 19)

The procedure described for Compound 1 is used, from amine VI and acidchloride XIX.

20. Preparation of2,4,6-triiodo-3-acetamido-5-(2,4,6-triiodo-3-N-methylacetamido-5-acetamido-benzoyl)-glycylamino-benzoicacid (Compound 20)

a.2,4,6-Triiodo-3-acetamido-5-(2,4,6-triiodo-3-N-methylacetamido-5-amino-benzoyl)glycyl-amino-benzoicacid (Compound 20a): Obtained as described for Compound 1, from amineVII and acid chloride XXV.

b. Acetylation of Compound 20a gives Compound 20.

21. Preparation of2,4,6-triiodo-3-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)glycyl-N-methylamino-benzoicacid (Compound 21)

a.2,4,6-Triiodo-3-(2,4,6-triiodo-3-N-methylcarbamyl-5-aminobenzoyl)glycyl-N-methylamino-benzoic acid (Compound 21a): Obtained using the proceduredescribed for Compound 1, from amine X and acid chloride XX.

b. Acetylation of Compound 21a gives Compound 21.

22. Preparation of2,4,6-triiodo-3-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-γ-aminobutyrylamino-benzoicacid (Compound 22)

The procedure described for Compound 1 is used, from amine XI and acidchloride XIX.

23. Preparation of2,4,6-triiodo-3-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-β-aminopropionylamino-benzoicacid (Compound 23)

The procedure described for Compound 1 is used, from amine XII and acidchloride XIX.

24. Preparation of acid2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-γ-amino-butyrylamino-benzoicacid (Compound 24)

The procedure described for Compound 1 is used, from amine XIV and acidchloride XIX.

25. Preparation of2,4,6-triiodo-3-acetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)glycylamino-benzoicacid (Compound 25)

The procedure described for Compound 1 is used, from amine VII and acidchloride XIX.

26. Preparation of2,4,6-triiodo-3-N-methylacetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)-glycylamino-benzoicacid (Compound 26).

a.2,4,6-Triiodo-3-N-methylacetamido-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoyl)-glycylamino-benzoicacid (Compound 26a): Obtained using the procedure described for Compound1, from amine XIII and acid chloride XX.

b. Acetylation of Compound 26a gives Compound 26.

27. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoyl)-glycyl-amino-benzoicacid (Compound 27)

The procedure described for Compound 1 is used, from amine III and acidchloride XX.

28. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-[2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)-glycylamino-benzoyl]glycyl-N-methylamino-benzoicacid (Compound28)

a.2,4,6-Triiodo-3-N-methylcarbamyl-5-[2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-aminobenzoyl)glycyl-amino-benzoyl]glycyl-N-methylamino-benzoicacid (Compound 28a): Obtained using the procedure described for Compound1, from amine XV and acid chloride XX.

b. Acetylation of Compound 28a gives Compound 28.

29. Preparation of2,4,6-triiodo-3-[2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)glycylamino-benzoyl]glycylamino-benzoicacid (Compound 29)

The procedure described for Compound 1 is used, from amine XVI and acidchloride XIX.

30. Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-[2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)glycylamino-benzoyl]glycylamino-benzoicacid (Compound 30).

The procedure described for Compound 1 is used, from amine XVII and acidchloride XIX.

31. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-bis{[2,4,6-triiodo-3,5-bis(N-hydroxyethylcarbamyl)-phenyl]carbamylmethyl}aminoacetamido-benzoicacid (Compound 31)

A solution of 2,4,6-triiodo-3-N-methylcarbamyl-5-aminoacetamide-benzoicacid (126 g; 0.2 mole) (Compound III) in N sodium hydroxide (220 ml) ismixed with a solution of2,4,6-triiode-3,5-bis(N-hydroxyethylcarbamyl)-chloroacetanilide (288 g)(XXVII) in N sodium hydroxide (400 ml). Heating is maintained at 85° Cduring 20 hours, with stirring. The solution is cooled to 20° C and madeacidic to pH 1. The resulting gum crystallizes after standing overnightat room temperature. The solid is suction filtered, washed with waterand dried, to give 280 g of crude acid. The crude acid is taken up intowater, adjusted at pH 7 with ammonia, a slight insoluble is filteredoff, and the product is made acidic to pH 1 with dilute (1/10)hydrochloric acid. The precipitate is suction filtered, washed withwater and dried, to give 224 g of crude acid.

Titration with sodium hydroxide: 112%.

Purification:

1. Ammonium salt: 224 g of acid are taken up into 150 ml water. Ammoniais added to neutrality. Crystallization occurs. The material is stirredduring 24 hours at room temperature. The precipitate is suctionfiltered, washed with water and taken up into 10N sodium hydroxide untildissolution is complete. This is then precipitated with hydrochloricacid, suction filtered, washed with water and dried, to give 155 g ofacid.

Titration with sodium hydroxide: 107%.

2. Methylglucamine salt: a methylglucamine salt solution, containing 28%iodine, is prepared with the 155 g thus obtained. The insoluble isremoved by centrifugation and filtration through millipore filter. Thefiltrate is made acidic to pH1 with hydrochloric acid. The precipitateis suction filtered, and this treatment is repeated once, to give 74 gof acid (overall yield: 18.5%).

Purity of the product is controlled by:

    ______________________________________                                        TLC, Silicagel plate, n-butanol/water/-                                       acetic acid (50:25:11)                                                        eluent: Rf of starting chloro material                                                                  0.75                                                Rf of starting amine      0.25                                                Rf of condensation product                                                                              0.25                                                Titration with 0.1N sodium hydroxide                                                                    103%                                                Titration with sodium methoxide                                                                         100%                                                Iodine titration           97%                                                ______________________________________                                    

32. Preparation of 2,4,6-triiodo-3-N-methylacetamido-5-bis{[2,4,6-triiodo-3,5-bis(N-Hydroxyethylcarbamyl)-phenyl]Carbamylmethyl}aminoacetamido-benzoicacid (compound 32)

The procedure described for Compound 31 is used, using amine XIIIinstead of amine III.

33. Preparation of 2,4,6-triiodo-3-N-methylcarbamyl-5-bis{[2,4,6-Triiodo-3,5-bis(N-hydroxyethylcarbamyl)-phenyl]carbamylmethyl}amino-N-methylacetamido-benzoicacid (compound 33)

The procedure described for Compound 31 is used, using amine VIIIinstead of amine III.

34. Preparation of2,4,6-triiodo-3-(2,4,6-triiodo-3-N-methylcarbamyl-5-aminobenzoyl)glycylamino-benzoicacid Compound 34)

The procedure described for Compound 1 is used, from amine VI and acidchloride XX.

35. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-gluconylamino-benzoyl)glycylamino-benzoicacid (Compound 35)

a. Condensation:

Using Compound 27 as starting material, a suspension is prepared fromCompound 27 (53.5 g; 0.045 mole) and dimethylacetamide (100 ml).Penta-acetyl gluconic acid chloride (39 g; 0.091 mole) (preparedaccording to C. E. BRAUN & C. D. COOK, Organic Syntheses, Vol. 41, pp78-82) is added thereto. The reaction mixture is stirred 24 hours atroom temperature. It is then poured over 500 ml water. The resulting gumcrystallizes after 48 hours in the refrigerator. It is suction filteredand repeatedly washed with water.

Tlc in eluent 1:

Rf of starting material: 0.5

Rf of condensation product: 0.35

b. The resulting crude product is dissolved in 300 ml ammonia. It isstirred overnight at room temperature, after which it is evaporated todryness in vacuo and taken up into 125 ml water. It is then made acidicwith dilute (1/2) hydrochloric acid. After 48 hours in the refrigerator,the precipitate is suction filtered and repeatedly washed with water; itis then dried, to give 35 g of product which is washed with 350 mlethanol. After suction filtering and drying, the acid is obtained in ayield of 30 g (i.e. an overall yield of 49%).

Purity control:

Tlc: eluent 1 : Rf 0.0

eluent 3 : Rf 0.25

eluent 4 : Rf 0.15

Titration with sodium hydroxide: 98%

Iodine titration: 100%

36. Preparation of2,4,6-triiodo-3-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-gluconylamino-benzoyl)glycylamino-benzoic acid (Compound 36)

It is prepared according to the procedure used for Compound 35, fromCompound 3a.

Tlc: eluent 1 : Rf 0.0

eluent 3 : Rf 0.15

eluent 4 : Rf 0.1

37. Preparation of2,4,6-triiodo-5-(2,4,6-triiodo-3-N-methylacetamido-benzoyl)glycyl-N-methylamino-benzoicacid (Compound 13, 2nd method)

Compound 12 (146 g; 0.13 mole) is dissolved in 4N sodium hydroxide(0.468 mole). Methyl iodide (0.338 mole) is added dropwise thereto,while cooling. After stirring 16 hours at room temperature, the reactionmixture is replenished (in an amount of 10%) with methylating agent and4N sodium hydroxide. After 48 hours of reaction, the material isprecipitated in acidic medium, to give, after repeated suctionfiltering, washing and then drying, 118.5 g (Yield of the methylation:72%).

Purity control:

1. TLC eluent 1

Unmethylated product: Rf 0.75

Methylated product: Rf 0.78 and 0.8

2. Eluent 2

Unmethylated product: Rf 0.4

Methylated product: Rf 0.4 and 0.5

3. Eluent 4

Unmethylated product: Rf 0.7

Methylated product: Rf 0.7 and 0.75

Purification: It is effected by salting out the ammonium salt: Yield80%.

Titration with sodium methoxide: 101%

Titration with sodium hydroxide: 97%

38. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamidobenzoyl)-glycyl-N-methylamino-benzoicacid (Compound 14, 2nd method)

a. Preparation of Compound 14a (2nd method):

Compound 27 (11.8 g; 0.01 mole) is dissolved in 2N sodium hydroxide (15ml; 0.03 mole) and acetone (4 ml). Methyl iodide (2.8 ml; 0.04 mole) isadded dropwise thereto. After stirring during 48 hours at roomtemperature, the reaction mixture is made acidic to pH 1, upon which aprecipitate is formed. After repeatedly suction filtering and washingwith water, the product is redissolved, adjusted at pH 3-4 andcharcoaled. It is then filtered, precipitated, suction filtered anddried, to give 9 g of product (Yield 75%).

Purity control

Tlc eluent 1.

Rf of starting material 0.5

Rf of methyl compound 0.6

Titration with sodium methoxide: 98%

b. Acetylation of 14a to 14 is carried out according to the usualtechniques, with CH₃ COCl in DMAC solution (Yield 40%).

39. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-γ-aminobutyryl-N-methylamino-benzoicacid (Compound 37)

Compound 2 (23 g; 0.082 mole) is dissolved in 5N sodium hydroxide (8.3ml; 0.0418 mole) and water (12 ml). Methyl iodide (5.9 g; 0.0418 mole)is added dropwise thereto. After stirring 24 hours at room temperature,the mixture is made acidic to pH 1. The precipitate is suction filtered,washed with water and dried, to give 20 g of crude acid.

Purification: this is effected by crystallization in the hot fromethanol (20 g/40 ml), under reflux during 3 days. After suctionfiltering, the product is taken up into alkaline medium and is thencharcoaled. After acidic precipitation, the product is suction filtered,washed with water and dried, to give 4.5 g of material (Yield 20%).

Purity control

Tlc, eluent 1:

Rf of unmethylated compound: 0.25

Rf of methylated compound: 0.55

Tlc, eluent 4:

Rf of unmethylated compound: 0.3 and 0.4

Rf of methylated compound: 0.35; 0.30 & 0.25

Titration with sodium hydroxide: 98%

Titration with sodium methoxide: 98%

40. Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-acetamido-benzoyl)glycyl-N-methylamino-benzoicacid (Compound 38) A. Preparation of2,4,6-triiodo-3-N-hydroxyethylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-amino-benzoyl)glycyl-N-methylamino-benzoicacid (Compound 38A)

Compound 38a is prepared according to the procedure described forCompound 14a, from Compound 3a, by methylation.

b. Compound 38 is obtained by acetylation of Compound 38a according tousual techniques.

41. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-β-aminopropionylamino-benzoicacid (Compound 39)

Compound 39 is obtained according to the procedure described forCompound 1, from amine XVIII and acid chloride XIX, heating time at 50°C being 3 hours. Crude Yield is 48%.

42. Preparation of2,4,6-triiodo-3-N-methylcarbamyl-5-(2,4,6-triiodo-3-N-methylcarbamyl-5-N-methylacetamido-benzoyl)-β-aminopropionyl-N-methylamino-benzoicacid (Compound 40)

Compound 40 is obtained by methylation of Compound 39.

In following Table V are set forth data relating to the preparation ofcompounds of the formula I and to the resulting compounds. Thestructural formulae of the compounds are given in Table VI.

                                      TABLE V                                     __________________________________________________________________________                        Yield                                                                              Rf in                                                        Star-       Acety-                                                                             eluent                                                       ting        lation                                                                             1                                                        Star-                                                                             acid    Rf in                                                                              +   after                       Rf                                                                                 Rf in               Com-                                                                              ting                                                                              chlo-                                                                             Crude                                                                             eluent                                                                            Saponi-                                                                            saponi-                                                                            Purification                                                                            Titration    eluent                                                                             eluent              pound                                                                             amine                                                                             ride                                                                              Yield                                                                              1  fication                                                                           fication                                                                           Method                                                                             Yield                                                                              NaOH                                                                              MeONa                                                                              I    1    4                  __________________________________________________________________________    1   I   XIX 61% 0.15          EtOH 62%  100%                                                                              100% 100%                                                                              0.15 0.3 and                                                                       0.4                 2   II  XIX     0.25          NH.sub.4.sup.+                                                                     73%  100%                                                                              98%  99.5%                                                                             0.25 0.3 and                                                                       0.4                 via I   XX  52% 0.2 54%  0.1  NH.sub.4.sup.+                                                                     70%  101%                                                                              99%  98.5%                                                                             0.1  0.1 in              3a          47%                                           eluent                          (I)                                           2                   3                   78%                                   0.1 in              via I   XXII                                                                              uniso-                                                                            0.2 after                                                                              0.1  NH.sub.4.sup.+                                                                     70%  101%                                                                              98%  99% 0.1  eluent              3b          lated   conden-                               2                                       sation                                                    4                                  17%                                        via II  XXIII                                                                             uniso-                                                                            2.25                                                                              uniso-                                                                             0.15 EtOH overall                                                                            104%                                                                              97%  96% 0.15                     4a          lated   lated          yield                                      5   IV  XIX 83% 0.20          NH.sub.4.sup.+                                                                     44%      100% 99% 0.2                      6                                                         0.15 and            via I   XXV 77% 0.20                                                                              76%  0.12 NH.sub.4.sup.+                                                                     32%  102%                                                                              99.3%                                                                              99.8%                                                                             0.12 0.2                 6a                                                                            7           uniso-  uniso-         54%                                        via II  XXIV                                                                              lated                                                                             0.20                                                                              lated                                                                              0.1  NH.sub.4.sup.+                                                                     overall                                                                             97%                                                                              97%  99% 0.10                     7a                                 yield                                      8           un-     uniso-                                                                             uniso-    43%                    0.3                 via III XXIV                                                                              iso-                                                                              0.25                                                                              lated                                                                              lated                                                                              NH.sub.4.sup.+                                                                     overall                                                                            95% 99%  98% 0.25 and                 8a          lated                  yield                  0.35                9   III XIX 55% 0.2           Prop 63%  98.5%                                                                             100% 99.5%                                                                             0.2  0.4 and                                           OH                          0.5                 10  V   XIX 68.5%                                                                             0.4 and       (4)  17%  100%                                                                              96%  98.5%                                                                             0.4  0.4                                 0.5 in                                    and                                 eluent                                    0.5                                 4                                                             11  II  XXI 89% 0.5           NH.sub.4.sup.+                                                                     45%  100%                                                                              96.5%                                                                              98.5%                                                                             0.5  0.25 in                                                                       eluent 2            12                                                   0.75                     via VI  XXVI                                                                              91% 0.8 81%  0.75 unpurified                                      13  X   XXI 95% 0.7 and       (4)       100%                                                                              100% 100%                                                                              0.7  0.7                                 0.75 in                                   and                                 eluent                                    0.75                                4                                                             14                                                   0.3                                                                                0.35                via VIII                                                                              XX  97% 0.5 55%  0.3  EtOH 51%  100%                                                                              99%  99% eluent                                                                             and                 14a                                                  2    0.4                 15  III XXV 83% 0.4           unpurified             0.40                                     0.3 and                                   0.3 and             16 via                                                                            IX  XX  84% 0.4 in                                                                            54%  0.08 (5)  45%  101%                                                                              99.5%                                                                              98%      0.35                16a             eluent                                                                        4                                                             17  IX  XIX 68% 0.15          (5)  45%  98% 100% 99%      0.3 &                                                                         0.35 &                                                                        0.40                18  III XXI 86% 0.35          EtOH 33%  102%                                                                              101% 99% 0.35 0.3 in                                            twice                       eluent 2                                                                      0.7 and             19  VI  XIX 94% 0.7 in        EtOH 41%  102%                                                                              101% 98% 0.52 0.45 in                             eluent        twice                       eluent                              4                                         2                   20 via                                                                            VII XXV 54% 0.25                                                                              96%  0.12 NH.sub.4.sup.+                                                                     35%      103% 97.5%    0.10 in             20a         (2) and      and                              eluent                              0.3      0.15                             2                   21 via                                                    0.3 in              21a X   XX  80% 0.7 94%  0.5  EtOH 33%  100%                                                                              102% 97% 0.5  eluent                                                                        2                   22  XI  XIX 73% 0.45          EtOH 15%  99% 99%  99% 0.65                                                   twice                                           23  XII XIX 90% 0.4           EtOH 66%  98% 98%  99.8%                                                                             0.4                                                    twice                                           24  XIV XIX 79% 0.15 in       EtOH +                                                                             47%  97% 97%  99%      0.15 in                             eluent        NH.sub.4.sup.+              eluent                              4                                         4                   25  VII XIX 38% 0.20          EtOH +                                                                             39%  90% 89%  97% 0.20                                                   NH.sub.4.sup. +                                 26 via                                                                        26a XIII                                                                              XX  69% 0.40                                                                              40%  0.20 NH.sub.4.sup.+                                                                     46%  98.5%                                                                             98.5%                                                                              99% 0.20                                              glacony-                                             27  III XX  73% 0.5 after                                                                              lation                                                                             (7)  49%  98%      100%                                                                              0.25 0.15                                    uniso-                                                                             0.25      overall                                                        lated          yield                                      28 via                                                                        28a XV  XX  97.2%                                                                             0.30 (6)                                                                          83%  0.15 EtOH 16%  99% 97.9%                                                                              98% 0.15                     29  XVI XIX 87% 0.35          NH.sub.4.sup.+                                                                     33%      104% 98% 0.35                     30  XVII                                                                              XIX 61% 0.5 in                                    0.5 in                              eluent                                    eluent 2                            2                                                             31  III     56% 0.25 in                                                                       eluent        NH.sub.4.sup.+                                                                     33%  103%                                                                              100% 97%      0.25                                4                                                             32  XIII    88% 0.13          EtOH 45%  98.5%                                                                             98.5%                                                                              98.5%                                                                             0.13 and                                 and           twice                  0.16 (6)                                 0.16 (6)                                                                                                                0.55 &              33  VIII    84% 0.25          NH.sub.4.sup.+                                                                     38%  98% 101% 100%                                                                              0.25 0.6 in                              (6)                                  (6)  eluent 2            34  VI  XX  90% 0.40          Used crude                                                                              99.5%        0.40                     36  I   XX  52% 0.2 after glu-                                                                              (7)  45%  99.7%                                                                             98%  100%                                                                              0.15 0.1                                     conyla-                                                                            0.25      overall                                                        tion un-                                                                      isolated       yield                                      39  XVIII                                                                             XIX 48%                                      0.2  0.45                                                                     0.25 0.65                40                                                   and                                                                           0.35                     __________________________________________________________________________     (1) After one crystallization from 500 ml refluxing ethanol                   (2) After one crystallization from ethanol (97 g in 150 ml, under reflux)     (3) After one crystallization from ethanol (405 g/500 ml, under reflux)       (4) Fractional precipitation, with water, of a solution in                    dimethylformamide                                                             (5) Precipitation, with isopropyl alcohol, of a methanol solution             (6) In eluent: isobutanol/isopropanol/ammonia (60:20:30)                      (7) Washing with ethanol.                                                

                                      TABLE VI                                    __________________________________________________________________________          ##STR42##                                                                     ##STR43##                                                                     ##STR44##                                                               3a.                                                                                 ##STR45##                                                               3b.                                                                                 ##STR46##                                                                     ##STR47##                                                               4a.                                                                                 ##STR48##                                                                     ##STR49##                                                                     ##STR50##                                                               6a.                                                                                 ##STR51##                                                                     ##STR52##                                                               7a.                                                                                 ##STR53##                                                                     ##STR54##                                                               8a.                                                                                 ##STR55##                                                                     ##STR56##                                                               10.                                                                                 ##STR57##                                                                     ##STR58##                                                                     ##STR59##                                                               12a.                                                                                ##STR60##                                                                     ##STR61##                                                                     ##STR62##                                                               14a.                                                                                ##STR63##                                                                     ##STR64##                                                                     ##STR65##                                                               16a.                                                                                ##STR66##                                                                     ##STR67##                                                                     ##STR68##                                                                     ##STR69##                                                               20.                                                                                 ##STR70##                                                               20a.                                                                                ##STR71##                                                                     ##STR72##                                                               21a.                                                                                ##STR73##                                                                     ##STR74##                                                                     ##STR75##                                                                     ##STR76##                                                                     ##STR77##                                                               26                                                                                  ##STR78##                                                               26a.                                                                                ##STR79##                                                                     ##STR80##                                                                     ##STR81##                                                               28a.                                                                                ##STR82##                                                                     ##STR83##                                                               30.                                                                                 ##STR84##                                                                     ##STR85##                                                                     ##STR86##                                                                     ##STR87##                                                                     ##STR88##                                                                     ##STR89##                                                                     ##STR90##                                                                     ##STR91##                                                                     ##STR92##                                                               38a.                                                                                ##STR93##                                                                     ##STR94##                                                               40.                                                                                 ##STR95##                                                               __________________________________________________________________________

d. preparation of injectable solutions

Pharmaceutical grade injectable solutions are prepared in the form ofthe methylglucamine or sodium salt, containing 28, 38 or 48 g iodine per100 ml (solutions said to contain 28%, 38% and 48% iodine).

After filling the product ino ampoules, under a nitrogen atmosphere, itis sterilized by heating at 120° C during 20 minutes.

The results of viscosity determinations of 28% methylglucamine saltsolutions, at 37° C, are given in following Table VII. It is apparent,from said results, that, contrary to expectations, the compounds of theformula (I) have relatively low solution viscosities.

                  TABLE VII                                                       ______________________________________                                        Compound      Viscosity, cps. at 37° C                                 ______________________________________                                                      5.4                                                             2             6.56                                                            3             5.72                                                            6             5.2                                                             8             5.5                                                             9             5.8                                                             14            5.2                                                             24            6                                                               31            10.2                                                            ______________________________________                                    

The results of osmolality determinations are given in following TableVIII.

Osmolality is determined by extrapolation of the values obtained onsuccessive dilutions of solutions containing 28% or 38% iodine.

Osmolality readings are made with a FISKE Model 230/D/330 D osmometer.This apparatus indicates this measurement as milliosmoles per kg ofsolution. Its operation is based on the principles of cryoscopy. Thedeterminations were made with solutions containing 28% iodine.

                  TABLE VIII                                                      ______________________________________                                                  Osmolality             Osmolality                                   Compound  mosm/kg     Compound   mosm/kg                                      ______________________________________                                        1         510         17         200                                          2         475         18         390                                          3         550         19         500                                          5         490         20         755                                          6         480         37         730                                          7         525         21         580                                          8         535         23         535                                          9         440         38         635                                          10        420         24         575                                          11        390         25         925                                          14        600         26         500                                          16        250         31         350                                                                32         270                                                                33         370                                          a*        1410                                                                b*        1390                                                                c*        950                                                                 ______________________________________                                         *a, b and c are the following reference compounds:                            a: 2,4,6-Triiodo-3-N-methylcarbamyl-5-acetamido-benzoic acid                  b: 2,4,6-Triiodo-3-N-hydroxyethylcarbamyl-5-acetamido-benzoic acid            c: 5,5'-Adipoyldiimido-bis-(2,4,6-triiodo-N-methylisophthalamic) acid.   

It is apparent that, as the glucamine salts, the compounds of theformula (I) possess an osmolality markedly lower than that of thereference compounds.

The results of a comparative toxicological and pharmacologicalinvestigation are given below.

Acute toxicity determination

Intravenous toxicity in mice

Intravenous toxicity determination was effected in Swiss origin, IOPSmice of OFI strain.

Each dosage level was injected to a lot of 10 mice comprising 5 male and5 female mice.

Injections were made manually, in the caudal vein, at a rate of 2ml/minute.

Death rate during the 24 hours after injection was recorded.

Biliary clearance test in cats

This test was conducted in male or female adult cats weighing 3-4 kg.

The test material was injected intravenously, at a dosage of 0.10 g/kgiodine at the level of the internal saphenous vein. Clearance of thematerial was monitored by X-ray control.

X-ray pictures visualizing the gall bladder and the bladder were takenat the following times: 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5hours, 6 hours.

Effect on the femoral rate of flow

This test was carried out in Nembutal-anesthetized male or female 7-12kg mongrels.

Nembutal was used at a dosage of 30 mg/kg, with Vetranquilpre-medication, (overall intravenous injection of 2.5 mg), respirationwas spontaneous.

Rate of flow variations were recorded at the level of the right or leftfemoral artery, by means of a Statham electromagnetic sensor.

The injections were made in a collateral of the femoral artery,downstream of the sensor, by means of a catheter mounted by theretrograde route, so as not to perturb the blood flow.

The injections were made under a constant volume of 1.5 ml administeredwithin 3-5 seconds.

The same volume of an isotonic sodium chloride solution was alsoinjected. The resulting data are tabulated in Table IX.

                  TABLE IX                                                        ______________________________________                                                                    Peripheral                                                                             Biliary                                  Com-  I content  Acute toxicity                                                                           vasodilatation                                                                         clearance                                pound Nature     in mice, i.v.;                                                                           Femoral rate                                                                           in cat; i.v.;                            No.   of the salt                                                                              grams I/kg of flow  0.10g I/kg                               ______________________________________                                        1     38%        11.5       +        ±                                           Mgl                                                                     2     28%        9.5        +        0                                              Mgl                                                                     3     28%        9-10       +                                                       Mgl                                                                     5     28%        6.8        ++++     ±                                           Mgl                                                                     6     28%        10         +        0                                              Mgl                                                                     7     28%        5          ++       0                                              Mgl                                                                     8     28%        12         ++       ±                                           Mgl                                                                     9     38%        11.5       +        ++                                             Mgl                                                                     10    28%        1.5        ++++     ++++                                           Mgl                                                                     11    28%        2.3        ++++     +++                                            Mgl                                                                     14    28%        12         +        +                                              Mgl                                                                     16    28%                   +        0                                              Mgl                                                                     17    28%                   ++       0                                              Na                                                                      18    28%                   ++++     ++++                                           Mgl                                                                     19    28%        4          ++++     ++++                                           Mgl                                                                     20    28 and 38% 7.5        +                                                       Na                                                                      21    20%        4-5        ++++     +++                                            Mgl                                                                     23    28%        3.5        +++      ++++                                           Mgl                                                                     24    28%        8.5        +        0                                              Mgl                                                                     25    34%        9          ++       0                                              Na                                                                      26    38%        13         ++       0                                              Na                                                                      31    28%        15         +        0                                              Mgl                                                                     32    28%        15         +        0                                              Mgl                                                                     33    38%        17         ++                                                      Na                                                                      35    28%        8          +        0                                              Mgl                                                                     36    28%        8          ++       0                                              Mgl                                                                     37    28%        <6         ++++     ++                                             Mgl                                                                     a     28%        5.4        +++      0                                              Mgl                                                                     b     30%        5.6        +++      0                                              Mgl                                                                     c     28%        6.2        ++       0                                              Mgl                                                                     d     38%        5.7        +++      0                                              mixed Mgl                                                                     and Na salt                                                             e     28%        2          ++++     ++++                                           Mgl                                                                     ______________________________________                                         a = 2,4,6-Triiodo-3-methylcarbamyl-5-acetamido-benzoic                        b = 2,4,6-Triiodo-3-N-hydroxyethylcarbamyl-5-acetamido-benzoic                c = 5,5'-Adipoyldiimino-bis(2,4,6-triiodo-N-methylisophthalamic)              d = 2,4,6-Triiodo-3,5-bis-(acetamido)-benzoic                                 e = 3,3'-Adipoyldiimino-bis(2,4,6-triiodo benzoic)                            The number of +'s is proportional to the effect observed.                

The results of a toxicological investigation effected in rats onintracisternal injection, according to E. Melartin's method(INvestigative Radiology 1970 5, 1, 13-21) are also set forth below.

    ______________________________________                                                    Dosage                                                            Compound    per rat       Death rate                                          ______________________________________                                        31          56 mg I       1/10                                                32          50 mg I       0/10                                                33          56 mg I       0/10                                                 c          17 mg I       9/10                                                ______________________________________                                    

It is apparent from the data reported above that the compounds of theformula (I) are useful as X-ray contrast media. The predominantapplications of said compounds are urography, angiography,cholangiography and myelography.

The preferred pharmaceutical form of the X-ray contrast media consistsof aqueous solutions of salts of the compounds of the formula (I).

The aqueous solutions contain advantageously 5-100 g of salt per 100 mland the injectable amount of such solutions may vary within the rangefrom 5 ml to 1,000 ml.

Having now described our invention what we claim as new and desire tosecure by Letters Patent is:
 1. An iodobenzene derivative selected fromthe group consisting of a compound of formula ##STR96## in which: R₁ isselected from the group consisting of a radical having the formula##STR97## R₅ and R₆ being each selected from the group consisting ofhydrogen, lower alkyl, lower hydroxyalkyl and lower alkanoyloxyalkyl anda radical of the formula ##STR98## R₇ being lower alkanoyl and R₈ beingselected from the group consisting of hydrogen, lower alkyl and lowerhydroxyalkyl,R₂ is selected from the group consisting of a radicalhaving the formula ##STR99## in which R₉ and R₁₀ have the meanings givenfor R₅ and R₆, and a radical of the formula ##STR100## in which R₁₁ hasthe meaning given for R₇ or represents hydrogen and R₁₂ has the meaninggiven for R₈, at least one of the radicals R₁ and R₂ being of ##STR101##R₄ is selected from the group consisting of hydrogen, lower alkyl andlower hydroxyalkyl, R₁₅ is selected from the group consisting ofhydrogen, lower alkanoyl and polyhydroxy lower alkanoyl, R₁₆ is selectedfrom the group consisting of hydrogen, lower alkyl, lower hydroxyalkyland lower alkanoyl,a is 0 or 1 n is an integer from 1 to 5 b is 1 or 2and the different R₂, R₄ and n which exist when b = 2 may have the sameor different meanings, a lower alkyl ester thereof and a salt with apharmaceutically acceptable base.
 2. An X-ray contrast medium comprisingan aqueous solution of an effective amount of a compound as claimed inclaim
 1. 3. An X-ray contrast medium comprising an aqueous solution ofan effective amount of a pharmaceutically acceptable salt of a compoundas claimed in claim
 1. 4. An X-ray contrast medium as claimed in claim 3in which 100 ml of said solution contains 5-100 g of said salt.